NorthStar Navigation 491 User Manual

491 ECHO SOUNDER

INSTALLATION MANUAL

Rev A

Part Number GM495

Northstar	www.NorthstarNav.com
a unit of Brunswick New Technologies Marine Electronics
30 Sudbury Road	Service: 978/897-6600
Acton, Massachusetts 01720	Sales: 800/628-4487

Table of Contents

SECTION ONE — Introduction					-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	1
Welcome to the Northstar 491								-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	1
Who should read this manual								-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	1
Scope of this manual				-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	1
Installation considerations						-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	2
SECTION TWO — Installing the transducer											- - - - - - -							-	-	-	-	-	-	-	3
Safety considerations				-	-	-	-	-	-	- - - - - - - -								-	-	-	-	-	-	-	3
Selecting a transducer				-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	4
Installation considerations						-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	5
Choosing a mounting location								-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	5
Installing the transducer					-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	7
Maintaining the transducer							-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	8
SECTION THREE — Installing the 491									-	-	-	-	-	-	-	-	-	-	-	-	-	-	-		11
Safety considerations				-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-		11
System components			-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-		13
Choosing a mounting location								-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-		14
Mounting the 491		-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-		14
Wiring the 491	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-		15
Initial checkout	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-		19
Installation test checklist						-	-	-	-	-	- - - - - - -							-	-	-	-	-	-		20
SECTION FOUR — Troubleshooting and servicing the 491																		-	-	-	-	-	-		21
Common 491 installation problems										-	-	-	-	-	-	-	-	-	-	-	-	-	-		21
The status LED	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-		21
Getting technical support						-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-		24
Ordering replacement parts							-	-	-	-	- - - - - - -							-	-	-	-	-	-		25
Servicing the 491		-	-	-	-	-	-	-	-	- - - - - - - -								-	-	-	-	-	-		25
Returning a 491 for service							-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-		26
APPENDIX A — Technical specifications										-	-	-	-	-	-	-	-	-	-	-	-	-	-		27
Glossary - - - - - - - - -				- -		- -		- -		-	-	-	-	-	-	-	-	-	-	-	-	-	-		29
Index - - - - - - - -	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-		31

SECTION ONE — Introduction

Welcome to the Northstar 491

An echo sounder is a device that provides information about the water directly beneath a vessel. The Northstar echo sounder system consists of:

•the Northstar 491 echo sounder sensor

•a Northstar navigation system such as the 962, 958 or 6000i

•a transducer

The 491 can be used with either a single-element transducer or a dual-element transducer. The 491 automatically pings both transmitters at power-up to determine the number of transducer elements connected. If a single element is detected, the 491 operates in single-frequency or dual-frequency interleaved mode (as determined by the operator) at 600 Watts. If two elements are detected, the 491 uses both elements at 1000 Watts.

Installation and setup procedures are different for the two basic types of Northstar navigators. The following terminology should be carefully followed:

•the term 961/962 indicates instructions that apply to the Northstar 961 and the 962 navigators

•the term 957/958/6000i is used for these units

•the term navigator by itself identifies information that applies to all units

Who should read this manual

Scope of this manual

This manual is for marine technicians who are installing the Northstar 491 and connecting it to a Northstar navigator and a transducer.

In this manual, you’ll find information about the following:

•mounting and wiring the 491

•connecting the 491 to the Northstar navigator

•installing a transducer (an overview is provided, but for such details as wiring, see the documentation provided by the transducer’s manufacturer)

491 INSTALLATION MANUAL Revision A

PAGE 1

SECTION ONE — Introduction

•connecting the 491 to a transducer (see also the Transducer Connector Instructions—GM492)

•troubleshooting and testing the system

•technical specifications for the 491

For information about obtaining technical support and returning the 491 for factory service, “SECTION FOUR — Troubleshooting and servicing the 491” beginning on page 21.

For details about operating the 491, see the Northstar 491 Echo Sounder Operations Manual (GM494) or Northstar 6000i’s Reference Manual, for that product.

Installation considerations

CAUTION! The following list of installation considerations isn’t a substitute for all the details in Section Three. To ensure that you meet all critical installation parameters, be sure to read that entire section and follow all of its recommendations.

1.Check the shipping carton for any damage, and immediately report any damage to the carrier. Save all packing material in case you have to return the 491 to the factory for repair or evaluation.

2.Unpack the carton, and check its contents. You should have received:

•the Northstar 491 Echo Sounder

•10-foot (3-meter) data cable to connect the 491 to the navigator

•10-foot (3-meter) power cable for the 491

•491 parts kit (containing transducer cable end connector, backshell, heatshrink tubing, and the Transducer Connector Instruc- tions—GM492)

•Northstar 491 Echo Sounder Installation Manual (GM495)

•Northstar 491 Echo Sounder Operations Manual (GM494)

•owner registration card

3.Fill out the owner registration card and mail it to Northstar.

4.Review all of the installation requirements as outlined in Sections Two and Three.

5.Install the transducer, then terminate the cable (see ”Connecting the 491 to a transducer” starting on page 18).

6.Mount the 491. For instructions, see ”Mounting the 491” beginning on page 14.

7.Connect the 491 to ship’s power and to the navigator. Connection information begins on page 15.

With the vessel in the water, turn on the system and verify proper operation.

PAGE 2

491 INSTALLATION MANUAL Revision A

SECTION TWO — Installing the transducer

Safety

considerations

WARNING! Be sure to turn the power off before starting the installation. Further, it is highly recommended that you keep power off while you’re performing the installation. If power is left on or turned on during the installation, fire, electrical shock, or other serious injury may occur.

Be sure to ground the equipment to prevent electrical shock and mutual interference.

Be sure the transducer outputs are tied together before handling to avoid electrical charge build-up.

WARNING! Be sure to use a 3-amp fuse. Using the incorrect fuse can result in fire or damage to the 491.

CAUTION! Mounting the transducer requires drilling holes through the hull; make sure the installation does not cause the vessel to leak. A thru-hull installation should be performed by a professional installer. Do not attempt this unless you are fully qualified.

Do not perform a thru-hull installation of the transducer when the vessel is actually in the water.

Immediately after installing the transducer, be sure to check for leaks, and don’t leave the vessel in the water for more than three hours before checking it again.

Northstar assumes no responsibility for improper installation of a transducer.

NOTE: Be sure that the transducer doesn’t interfere with any of the on-board systems. Check all other systems to ensure that their performance doesn’t degrade when the transducer is connected.

491 INSTALLATION MANUAL Revision A

PAGE 3

SECTION TWO — Installing the transducer

Selecting a transducer

Northstar recommends using an Airmar transducer with the Northstar 491 echo sounder. The Airmar B260, B744 and P66 can be obtained from Northstar as an installation kit with connectors installed.

Table 1: Northstar-recommended transducers

Manufacturer	Housing	Power	Frequency	Northstar P/N
Airmar	B260	1 kW	50/200 kHz	TD1004
Airmar	B744V/B44V (with	600 W	50/200 kHz	TD1005
	3-wire speed)
Airmar	P66	600 W	50/200 kHz	TD1006

A table of Airmar transducer elements is given below to assist in evaluating characteristics of other Airmar transducers.

Table 2: Airmar transducer elements

Transducer	Single	Used in	Acoustic	Beam	Beam	Rated
element	or Dual	Airmar	material	Width	Width	Power
	element	P/N		(50	(200 kHz)
				kHz)
50/200A	Single	B744V	Urethane	45°	12°	600W
		B744VL
		P319
		B117
		SS555
50/200A	Single	P66	LPU	45°	11°	600W
		P79
		P74
50/200B	Single	B256	Urethane	23°	5°	1200W
50AE/200Riq	Dual	B45	Urethane	19°	6°	1000W
		B250-B
		B260

Dealers can also purchase quantities of transducers directly from Airmar

Technology Corporation at:

Airmar Technology Corporation

35 Meadowbrook Drive

Milford, New Hampshire 03055-4613

Phone [phone]

Fax [phone] (www.airmar.com)

PAGE 4

491 INSTALLATION MANUAL Revision A

Installation considerations

SECTION TWO — Installing the transducer

The following basic setup information isn’t a substitute for the installation instructions provided by the transducer’s manufacturer. To ensure that you meet all critical installation parameters, be sure to read and follow all of the requirements in their instructions. Northstar assumes no responsibility for improper installation.

Choosing a mounting location

Choose the mounting location to obtain the best possible performance from the transducer and the 491.

Take into account the vessel’s maximum speed when selecting a mounting location, as turbulence can affect echo sounding capabilities.

CAUTION! Do not mount the transducer:

behind strakes, fittings, or hull irregularities (mounting in those locations may increase turbulence, aeration, and cavitation) or near the keel

near openings for water intake or discharge

where it might be loosened by the vessel’s vibration

less than four feet away from the Northstar 961/962 processor or other similar equipment to minimize interference

The two most common problems with echo sounder installations stem from electrical noise and cavitation. Either of these situations can produce poor performance.

Electrical noise occurs when the transducer cable is routed too closely to noise-producing electronics, such as alternators, AC generators, radars, etc. To avoid problems with noise, route the transducer cable by itself (not in a bundle) and away from other wires or cables and the engine.

Cavitation can occur at high speeds. During cavitation, bubbles form between the transducer and the water. When this happens, the transducer can’t get its energy into the water properly and won’t be able to detect any echoes. To avoid cavitation, choose a mounting location with good water flow all around it at all speeds.

Before any drilling or cutting takes place, carefully choose a mounting location for the transducer that meets the following criteria (also see Figure 1 on page 7), depending on the type of vessel:

•the transducer is more than four feet away from the Northstar navigator and other similar equipment, to prevent mutual electrical and magnetic interference

•the transducer and its cable are as far as possible from other electrical cables

•there is space above the transducer for the transducer’s stem, housing, and cable

491 INSTALLATION MANUAL Revision A

PAGE 5

SECTION TWO — Installing the transducer

•the path for running the transducer’s cable is reasonably direct—keep in mind that the transducer cable is 33 feet long (10 meters). To prevent damage, coil any excess cable and secure it

•water turbulence and noise are minimal, decreasing the amount of bubbles passing over the transducer face

•the transducer isn’t behind hull irregularities or near eroding paint; both indicate areas subject to turbulence

•the transducer is as far as possible from the engine or propellers, and inboard of the lifting strakes

•the transducer always remains submerged and parallel to the water surface

•the transducer is easily accessible from inside the vessel for adjustments and maintenance

•the transducer’s ultrasonic beams aren’t obstructed by the keel, propeller shafts, or any other part of the vessel

•the hull thickness falls within the limits in Table 3 below (all dimensions are perpendicular to the waterline):

Table 3: Hull thickness limits

Model	Minimum	Maximum
AirMar B44V/B744V with fairing	6 mm (1/4 inch)	19 mm (3/4 inch)
AirMar B44V/B744V without fairing	6 mm (1/4 inch)	65 mm (2 1/2 inches)
AirMar B260 with fairing	——	45 mm (1 3/4 inches)
AirMar B260 without fairing	19 mm (3/4 inch)	114 mm (4 1/2 inches)

PAGE 6

491 INSTALLATION MANUAL Revision A

Installing the transducer

SECTION TWO — Installing the transducer

pressure waves

	1/3 aft
	LWL	150-300mm
	(Load Waterline Length)
		(6-12")

displacement hull

outboard and I/O

planning hulls	inboard

step-hull

fin keel sailboat

full keel sailboat

Best location for the transducer

FIGURE 1: Recommended installation locations for a transducer

A flat-bottom hull provides the best environment for mounting the transducer: It provides a horizontal surface and a constant water flow over the transducer, with little turbulence (see Figure 2 for the recommended transducer incline angle). If the vessel has a deadrise angle greater than 5 degrees, mount the transducer on a fairing block to create a horizontal surface and keep the transducer perpendicular to the waterline (see Figure 3). You must order the fairing block, if needed, from the transducer’s manufacturer.

491 INSTALLATION MANUAL Revision A

PAGE 7

SECTION TWO — Installing the transducer

3˚ incline angle

1/3 aft

LWL

(Load Waterline Length)

FIGURE 2: Recommended transducer incline angle

	backing
	block	slope of hull
		deadrise
	hull	angle
		parallel to
		waterline
		fairing
	fairing thickness
	at narrowest point	multisensor
	6–12mm (1/4–1/2")

Deadrise angle and fairing thickness (B44V shown)

Maintaining the transducer

Using anti-fouling paint

FIGURE 3: Typical finished thru-hull installation with a fairing block (Airmar B744V)

Do not expose the transducer’s face or plastic housing to gasoline or strong solvents, such as acetone. These solvents can penetrate and degrade many plastics and reduce their strength.

The transducer should be coated with water-based anti-fouling paint to prevent aquatic growth.

PAGE 8

491 INSTALLATION MANUAL Revision A